This invention relates to a circuit for a telephone line power strip off which is capable of recovering of the order of 80% of the power presented to the terminals of the phone. Switch mode power supply regulators are used to achieve this efficiency along with a re-design of much of the "front end" of the phone.
The amount of power extracted from the line determines the level of features and performance of the phone. Previous products have had to exceed the D.C. voltage requirements (with permission from the Telephone Regulating Authorities). It is unlikely that such permission will be granted in the future and thus it is necessary to produce circuits which extract power from the line efficiently. It is an object of the present invention to produce such a circuit which takes power from the line efficiently and therefore allows the features and performance characteristics of the phone which are currently available, but still meeting the voltage requirements.